Electric fuse



May 25 1926. Y 1,585,647

' H. T. BUSSMANN ELECTRIC FUSE Original Filed May 7, 1919 Arm/W PatentedMay 25, 1926.

UNITED STATES PATENT OFFICE.

ELECTRIC FUSE.

Original application filed May 7, 1919, Serial No. 295,372. Divided andthis application filed January 17, 1922. Serial No. 529,968.

This application is a division of application Serial No. 295,372 filedMay 7, 1919.

My invention relates to electric fuse links and the object of myinvention is to provide a fuse link that will operate satisfactorilyunder any conditions.

In the drawings, Fig. 1 shows a view of my improved fuse link and Fig. 2an elevational View thereof. Fig. 3 shows a detailed view.

The fuse link has its center portion covered with insulating material 7This serves to conduct the heat away from that portion of the strip andcauses the strip to blow at the narrow uncovered portions 4:, allowingthe center section to drop out. and break the are. Where it is desiredto have the strip burn out at more than two points, additionalindependent sections of insulating material are placed on the centerportion.

On the blowing of fuse links an are continues which burns back on theterminal portions of the link. These terminal por- 'ti0ns being ofgreater width than the active portion of the strip, it can be seen thatthe amount of metal vaporized is very considerably increased because ofthis action.

I overcome this by providing a hard,

tenacious, closely adhering insulating material 5 to act as an arcshield on the terminal-portions 6, in addition to the insu-' latedsection or sections on the center portion, so that when the fuse isblown and the center portion or portions drop out, that the arc willbequickly extinguished.

I have also found that by using a hard,

tenacious adhering material, preferably moulded mica, or bakelite,condensite, or like materials, placed or compressed on the 40 centerportion, that I can obtain better results than with other materials thathave been used heretofore, as this material will, in addition toconducting the heat away from that portion of the strip, act as aneffective are shield by reason of its being able to withstand the highheat and explosive effect of the are.

What I claim is:

1. A fuse link having an area of reduced cross section and an area ofsolar ed cross section and an arc shield protecting that surface of theenlarged cross section facing the area of reduced cross section.

2. A fuse linkhaving terminal areas and an area of reduced cross sectionintermediate the terminal portions and an insulating material rotectingthat surface of the terminal portions facing the reduced cross section.

3. A fuse link having a pluralit of read ily fusible portions and anarea 0 enlarged cross section and an arc shield protecting a portion ofthe surface of the enlarged cross section facing the readily fusibleportions. 4

4. A fuse'link having an area of reduced cross section and an enlargedportion contiguous thereto and an insulating material covering thenarrow surface of the enlarged portion abutting on and facing thereduced area.

HENRY T. BUSSMANN.

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